1. Field of the Invention
The present invention relates to an infrared ear thermometer which is inserted into an external ear canal and detects an infrared radiation to estimate a body temperature, and a temperature state estimation method, an information notification method, and a measurement operation management method thereof.
2. Description of the Related Art
An infrared ear thermometer measures a dose of infrared ray radiated from an ear drum to determine a body temperature. A temperature detection unit of the infrared ear thermometer is constituted by an infrared sensor which captures an infrared radiation and a temperature sensor which measures the temperature of the sensor itself, and measures a target temperature by using output signals from the infrared sensor and the temperature sensor. As an ideal measurement condition, it is required that the temperature of the infrared sensor and the temperature of the temperature sensor are equal to each other. However, in actual use, these temperatures are different from each other, and measurement body temperature accuracy is deteriorated. In particular, when an environment temperature (atmospheric temperature) at which the clinical thermometer is placed sharply changes before and after the measurement, different heat flows are generated from the clinical thermometer to the infrared sensor and the temperature sensor. A temperature difference between the sensors is generated. As a result, the body temperature measurement value has an error.
For this reason, in a conventional clinical thermometer, in measuring a body temperature by detecting an environment temperature, when the environment temperature is different from a normal room temperature, the environment temperature is checked to see if it is stabilized and whether the body temperature can be measured. When the environment temperature is detected as described above, in the prior art, the environment temperature and a change in the environment temperature are detected by a change in temperature of the temperature sensor of the clinical thermometer. Furthermore, a temperature measurement value is also corrected in consideration of the environment temperature.
However, when a change in environment temperature is detected by using a change in temperature of the temperature sensor of the clinical thermometer, even though the change of the temperature sensor is converged in a state in which the temperature of the temperature sensor and the temperature of the infrared sensor are different from each other, a measurement error is not converged, and the temperature measurement value has an error. When the temperature measurement value is corrected in consideration of the environment temperature, accurate correction cannot be performed in a state in which the environment temperature changes.
The present invention has been made to solve the problems of the prior art, and provides a clinical thermometer which can perform accurate measurements by properly estimating the environment temperature and a thermometer temperature.
The present invention is an infrared clinical thermometer including: infrared detector for detecting infrared rays; infrared detection temperature measurement unit for measuring a temperature of the infrared detector or a temperature of a nearby position; at least two temperature measurement units for measuring temperatures of positions having different thermal environments; temperature state estimation unit for estimating a temperature state of at least one of the body of the clinical thermometer and the environment in which the clinical thermometer is placed based on the temperature measured by the temperature measurement unit; and body temperature estimation unit for estimating a body temperature of a test subject based on a dose of infrared ray detected by the infrared detector, the temperature measured by the infrared detection temperature measurement unit, and the temperature state estimated by the temperature state estimation unit.
When the temperatures of the positions having different thermal environments are measured, a thermal time constant of a part between these positions is calculated, and the thermal time constant is converted to obtain a thermal time constant of an arbitrary position. For this reason, one or both of the temperature states of the clinical thermometer body and the environment in which the clinical temperature is placed can be accurately estimated. Therefore, in not only a case in which the environment temperature is stable, but also in a case in which the environment temperature and the temperature of the clinical thermometer body change, the clinical thermometer can appropriately cope with the changes in temperature, and accurate body temperature estimation can be performed regardless of the position where the clinical thermometer is held and the position where the clinical thermometer is used.
The different thermal environments mentioned here are, e.g., environments in which thermal time constants around positions where the temperature measurement unit are arranged are different from each other, and indicate environments in which heat flows from a surrounding area to the temperature measurement unit. As the temperature measurement unit, at least two temperature measurement units may be used. One of the temperature measurement units may be the same as the infrared detection temperature measurement unit.
The temperature state estimation unit preferably includes an environment temperature change index calculation unit for calculating an environment temperature monotonously changed with respect to a change in environment temperature based on the temperature measured by the temperature measurement unit.
As the environment temperature change index monotonously changed with respect to the change in environment temperature, for example, a function such as a linear expression which uses, as variables, a change rate of a temperature of a first position which is easily influenced by the environment in which the thermometer is placed and a difference between a temperature of a second position which is any position (may be a typical position of the inside of the thermometer) in the thermometer body and the temperature of the first position is used.
The environment temperature change index calculated by the environment temperature change index calculation unit is preferably an index which is correlated to an estimation error of a body temperature.
The environment temperature change index which is correlated to the estimation error of the body temperature is more preferably an index which changes as well as the estimation error of the body temperature and which can equated with the estimation error.
The temperature state estimation unit preferably estimates at least one of temperature states of the body of the clinical thermometer and the environment in which the clinical thermometer is placed based on a change pattern of the temperature measured by the temperature measurement unit.
As the change pattern of the measured temperature, for example, a combination of a positive or negative sign (including 0) of the temperature of the first position which is easily influenced by the environment in which the clinical thermometer is placed and a positive or negative sign (including 0) of a difference between the temperature of the second position which is any position (may be a typical position of the inside of the thermometer) in the thermometer body and the temperature of the first position is known. However, the change pattern is not limited to this combination.
The infrared clinical thermometer preferably causes the temperature state estimation unit to estimate that a temperature state corresponding to a state obtained immediately after the clinical thermometer is used for a test subject is set.
The state obtained immediately after the clinical thermometer is used for a test subject unit a state in which a temperature state (heat) obtained when the test subject uses the clinical thermometer remains in the body of the clinical thermometer, and does not always mean a state obtained temporally immediately after the clinical thermometer is used for the test subject.
The infrared clinical thermometer preferably discriminates a temperature state corresponding to the state obtained immediately after the clinical thermometer is used for a test subject from a temperature state corresponding to another change in environment temperature.
The infrared clinical thermometer preferably inhibits body temperature measurement by the clinical thermometer until the environment temperature is stabilized when the temperature state corresponding to the change in environment temperature is estimated by the temperature state estimation unit.
The infrared clinical thermometer preferably includes a process selection unit for selecting a process performed when the temperature state corresponding to the state obtained immediately after the clinical thermometer is used for the test subject.
The infrared clinical thermometer preferably includes a temperature state notification unit for notifying a user of the temperature state.
In this manner, since a user can properly perform body temperature measurement with a small estimation error, a more correct body temperature estimation value can be obtained. Since the recognition of the use about a proper position and a measurement position of the clinical thermometer is improved, correct body temperature measurement can be performed within a short period of time.
As the notification unit, a display unit for notifying the user through visual sensation such as characters, graphics, light, or colors or voice generation unit for notifying the user through auditory sensation such as sound may be used. The notification unit is not limited to these means, and any means for exciting the five senses of the user to cause the user to recognize a temperature state may be used. The notification unit can preferably recognize temperature states changed by gradually changing notification contents or methods. The gradual notification is more preferably performed such that the user can recognize that a state is close to a state suitable for body temperature measurement.
The infrared clinical thermometer preferably includes a temperature state notification unit for notifying a user of the temperature state, and the temperature state notification unit preferably notifies the user of a temperature state regulated depending on the value of the environment temperature change index.
The infrared clinical thermometer preferably includes a temperature state notification unit for notifying a user of the temperature state, and the temperature state notification unit preferably notifies the user of the temperature state such that the temperature state is related to an estimation error of a body temperature.
The infrared clinical thermometer preferably includes a temperature state notification unit for notifying a user of the temperature state, and the temperature state notification unit preferably notifies the user of the temperature state such that the temperature state is related to reliability of a body temperature.
The infrared clinical thermometer preferably includes a measurement operation management unit for inhibiting and permitting body temperature measurement by the clinical thermometer depending on the temperature state estimated by the temperature state estimation unit.
In order to inhibit the body temperature measurement, a power supply of the clinical thermometer may be turned off to inhibit the use itself of the clinical thermometer, a detection operation of a dose of infrared rays may be inhibited, or detected or measured data may be voided by disposition or the like to inhibit the body temperature measurement.
The measurement operation management unit preferably determines whether the estimation of a temperature state by the temperature state estimation unit is continued depending on the temperature state when the temperature state in which the body temperature measurement is to be inhibited is set.
Even in a temperature state in which a body temperature is not appropriately measured, an estimation process of the temperature state may be repeated, and the temperature state may change into a temperature state in which body temperature measurement can be performed as time goes on. When the temperature state estimation process is continued by a determination made by the measurement operation management unit, measurement can be performed even in such a case. For this reason, user convenience is improved.
The infrared clinical thermometer preferably has a management information notification unit for notifying a user that at least one of an inhibition state and a permission state of the body temperature measurement by the clinical thermometer is set.
The notification which notifies the user that at least one of an inhibition state and a permission state of the body temperature measurement by the clinical thermometer is set includes not only a case in which the user is notified that the body temperature measurement is directly inhibited or permitted, but also a case in which the user is notified that the body temperature measurement is indirectly inhibited by notifying the user of information notified only when the body temperature measurement is inhibited and a case in which the user is notified that the body temperature measurement is indirectly permitted by performing a notification process such as display for causing the user to perform a normal measurement operation.
The infrared clinical thermometer preferably includes a measurement operation management unit for inhibiting and permitting body temperature measurement by the clinical thermometer depending on a value of the environment temperature change index and management information notification unit for notifying the user that at least one of an inhibition state and a permission state of the body temperature measurement by the clinical thermometer is set, and the measurement operation management unit preferably sets a reference value of an environment temperature change index for deciding whether the body temperature measurement by the clinical thermometer is inhibited or permitted based on a change pattern of a temperature measured by the temperature measurement unit.
The infrared clinical thermometer preferably estimates the temperature state by the temperature state estimation unit until a body temperature of a test subject is measured after a power supply is turned on.
When the temperature state estimation timing is limited, the temperature state can be accurately estimated without complicating the process.
The infrared clinical thermometer preferably includes an environment temperature estimation unit for estimating a temperature of an arbitrary point of an external environment of the clinical thermometer.
When the temperature itself of the external environment of the clinical thermometer is estimated as described above, a more exact process can be performed in estimation of a temperature state of at least one of the body of the clinical thermometer and an environment in which the clinical thermometer is placed.
The infrared clinical thermometer preferably includes an internal temperature estimation unit for estimating a temperature of an arbitrary portion of the clinical thermometer interior based on the temperature measured by the temperature measurement unit.
When the temperature itself of the arbitrary portion in the clinical thermometer body is estimated, a more exact process can be performed in estimation of a temperature state of at least one of the body of the clinical thermometer and an environment in which the clinical thermometer is placed.
The infrared clinical thermometer preferably turns off a power supply of the clinical thermometer depending on the temperature state estimated by the temperature state estimation unit.
The present invention is a temperature state estimation method for infrared clinical thermometer which estimates a temperature state of at least one of a body of an infrared clinical thermometer and an environment in which the clinical thermometer is placed, including: measuring temperatures of portions having different thermal environments in the clinical thermometer; and estimating the temperature state based on the measured temperature.
The temperature state estimation method includes calculating an environment temperature change index monotonously changed with respect to a change in environment temperature based on the measured temperatures of the portions having different thermal environments in the clinical thermometer, and the temperature state is preferably estimated based on the environment temperature change index.
The temperature state estimation method includes calculating change patterns of the measured temperatures of the portions having different thermal environments in the clinical thermometer, and the temperature state is preferably estimated by the environment temperature change index and the change patterns of the measured temperatures.
The present invention is an information notification method in infrared clinical thermometer which notifies a user of information in an infrared clinical thermometer, including: measuring temperatures of portions having different thermal environments in the clinical thermometer; estimating a temperature state of at least one of the body of the clinical thermometer and an environment in which the clinical thermometer is placed based on the measured temperatures; and notifying the estimated temperature state.
The method preferably includes calculating an environment temperature change index which is an index monotonously changed with respect to a change in environment temperature and which is related to an estimation error of a body temperature based on the measurement temperatures of the portions having different thermal environments in the clinical thermometer, the temperature state is estimated based on the environment temperature change index, and the estimated temperature state is notified such that the temperature state is related to an estimation error of the body temperature.
The present invention is a measurement operation management method for infrared clinical thermometer which inhibits and permits body temperature measurement by an infrared clinical thermometer including: measuring temperatures of portions having different thermal environments in the clinical thermometer; estimating the temperature state based on the measured temperatures; inhibiting or permitting the body temperature measurement by the clinical thermometer based on the estimated temperature state; and notifying a user that the body temperature measurement by the clinical thermometer is inhibited or permitted.
The present invention is a measurement operation management method for infrared clinical thermometer which inhibits and permits body temperature measurement by an infrared clinical thermometer, including measuring temperatures of portions having different thermal environments in the clinical thermometer; estimating the temperature state based on the measured temperatures; inhibiting or permitting the body temperature measurement by the clinical thermometer based on the estimated temperature state; notifying a user the temperature state such that the temperature state is related to an estimation error of a body temperature; and notifying the user that the body temperature measurement by the clinical thermometer is inhibited or permitted.
These together with other aspects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.